This invention relates generally to a fluid bearing track assembly, and, more particularly to a multiple level air bearing track assembly capable of interchangeably and/or simultaneously transporting silicon wafers of various diameters commonly used in the electronics industry.
Fluid bearing track assemblies find great utility in handling or transporting various articles, particularly fragile articles which do not lend themselves readily to manual handling during processing or treatment thereof. One such area of use for fluid bearing track assemblies is in the processing of semiconductor wafers, commonly used in the electronics industry in the manufacture of integrated circuits, transistors and semiconductor devices, during movement of such wafers between predetermined locations at which various operations and manufacturing activities are performed.
In particular, in the automated system for epitaxial deposition of silicon-on silicon wafers, wafers of varying diameters must be transported between a plurality of processing stations. Such an automated system operates under the supervisory control of a computer and operates without interruption. The automated functions incorporated within the system include a wafer cleaning station, surface inspection station for contamination, reactor station and evaluation station for electrical and physical characteristics of the wafer.
Heretofore, the fluid bearing assembly utilized to transport wafers between stations had to be physically or mechanically altered to accommodate the wafers of different diameters. Such a procedure considerably affects the operation of the automated wafer processing system. Not only does the inability of past fluid bearing transport assembly fail to accommodate various sized wafers and thereby substantially reduce the overall speed of operation of wafer processing equipment, but also past transport assemblies required additional operators to insure the efficient, reliable operation of the entire system. It is therefore clearly evident that the addition of a fluid bearing transport assembly capable of transporting various diameter silicon wafers without having to physically change the structure of the air bearing would greatly improve overall reliability and economy of operation, especially in the area of automated processing of semiconductor wafers.